sign in sign up
<<
Home , Late Pleistocene, Older Dryas, Pechora (river), Selizharovo, Vychegda

[RADIOCARBON, VOL. 35, No. 3, 1993, P. 421-427]

LATE GEOCHRONOLOGY OF EUROPEAN

KU. A. ARSLANOV

Geographical Research Institute, St. Petersburg State University, St. Petersburg 199004 Russia

14C ABSTRACT. I constructed a geochronological scale for European Russia employing dating and paleo- botanical studies of several reference sections.

MIKULIN0 (RISS-WURM) AND EARLY VALDAI (EARLY WURM) STAGES AND INTERSTADIALS 230Th/ I employed a modified 4U dating method (Arslanov et al. 1976, 1978, 1981) to determine shell ages. I learned that 232Th is present only in the outer layer of shells; thus, it is not necessary to correct for 230Th if the surface (-30% by weight) is removed. A great many shells were parallel- dated by 14C and 23°Th/234U methods; results corresponded well for young shells (to 13-14 ka). Older shells appear to be younger due to recent carbonate contamination. Shells from transgression sediments of the Barents, White and Black Seas were chosen as most suitable for dating, based on appearance. Table 1 presents measured ages for these shells. The data show that the inner fractions of shells sampled from (Eem) transgression deposits of the Barents and White Seas date to 86-114 ka. Shells from sediments of the Black Sea Karangat transgression, which correlates to the Boreal, date to 95-115 ka. 23°Th/234U dating of shells and coral show that shells have younger ages than corals; this appears to result from later uranium penetration into shells (Arslanov et a1.1976). Boreal transgression sediments on the Kola peninsula can be placed in the Mikulino interglacial based on shell, microfauna, diatom and pollen studies (Arslanov et at. 1981). According to the oxygen-isotope record from deep-sea cores, interglacial substage 5e corresponds to the Dilikulino (Eem, Sangamon) interglacial in the interval 128-116 ka (Morley and Hays 1981). By considering the trend of 23°Th/234Th age reduction for shells, it can be stated that the Karangat and Boreal transgressions (85-115 ka) correlate to the Mikulino interglacial.

Distinct cooling at the end of the Mikulino (Early Valdai) is identified from pollen studies of the Krotkov Cape liman clays (Taman peninsula) (Arslanov et al. 1983). Mollusk shells from the middle of the clays date to 95-100 ka (Table 1). Tree pollen comprises 93-98% of total pollen, with 55-65% , 27-35% fir and 12% . This association indicates forest. According to oxygen-isotopic, micropaleontologic and geochronologic investigations of ocean sediments, coral terraces and continuous lake and bog sections, abrupt climatic cooling occurred from 116-110 ka (Worm I). The Kurgolovo of the Russian plain glacial zones appears to correspond to this cooling. During the Mikulino interglacial and Early Valdai interstadial, loess loams interbedded with soil horizons were deposited in Russian plain periglacial regions (Velichko 1977). Two world- wide transgressions occurred in the Early Worm at ca. 100-105 and 80-85 ka BP and are recorded by the presence of emerged coral terraces on Barbados, in the eastern Caribbean Sea, and and Timor, in the southwest Pacific Ocean. Widespread continental sediments of two Early Wurm interstadials (Amersfort/Brerup and Odder- ade in western , Tarasovo and Kruglizky in Belorussia, Jonenis I and Jonenis II in Lithuania) correspond to the two oceanic transgressions discussed above. These sediments are well defined in the Grande-Pile section (France) and correspond to substages 5c and 5a of the oxygen- isotope scale (Woillard and Mook 1982).

421 422 Kh. A. Arslanov

TABLE 1.23°Th/4U Ages of Marine Mollusk Shells from Barents, White and Black Sea Trans- gression Sediments (A = outer fraction, B = inner fraction) Laboratory number Age Mollusk species and location

LU-455B 97,000 t 4000 Cyprina islandica from the section base, Svjatonossky gulf, Kola peninsula LU-452A 102,000 t 4000 Astarta borealis from the Malaja LU-452B 114,000 t 4000 Kachovka exposure, Kola peninsula LU-464A 85,500 t 3200 Cyprina islandica from the exposure LU-464B 86,000 t 3900 On Chapoma River, Kola peninsula LU-808A 129,400 t 4900 Cardium edule from the marine sediments of Maly Kut section, Taman peninsula LU-808B 115,000 t 3100 Same as above LU-805A 125,000 t 5000 Paphia senessens from the middle part of the marine sediments of Eltigen section, eastern coast of Kerch strait LU-805B 102,290 t 3200 Paphia senessens from the middle part of the marine sediments of Eltigen section, eastern coast of Kerch strait LU-802A 90,600 t 3100 Cardium tuberculatum from the same layer LU-802B 107,400 t 3800 Cardium tuberculatum from the same layer LU-804-1A 88,900 t 2200 Cardium edule from the Krotkov cape section, western part of Taman peninsula LU-804-1B 98,000 t 2400 Same as above LU-804-2A 98,900 t 2200 Same as above LU-804-2B 100,500 t 2100 Same as above

Early Valdai interstadials followed the main Early Valdai (WUrm) glacial stage. This interstadial (isotopic stage 4) ranges from 72-58 ka (Morley and Hays 1981); the polar front migrated south to 45°N latitude (Ruddiman and McIntire 1977). Scandinavian ice sheets expanded south to latitude only during this stage; southernmost (Sconia) was not affected by Wi rm glaciation earlier than 21 ka (Berglund and Lagerlund 1981).

Early Valdai sediments were studied in the following sections: Shestichino in the Jaroslavi region, Kileshino (near Selizharovo) in the region and Migovo (near Grodno) in Belorussia. According to paleobotanical data (F. J. Velichkevich and E. A. Spiridonova), these sediments deposited in and tundra-forest conditions date to >47-49 ka (Arslanov 1975; Spiridonova et al. 1981). To date, the Early Valdai (Visla) glacial cannot be identified on the Russian plain, nor over much of western Europe.

THE MIDDLE VALDAI NON-GLACIAL INTERVAL

The interval between Early and Late Valdai glaciation includes the Middle Valdai interstadial complex (mega-interstadial), which contained warming and cooling phases. 14C dating of plant remains shows that the Middle Valdai (Worm, Visla) mega-interstadial continued from 58-60 to 25 ka (Arslanov 1975; Woillard and Mook 1982), and according to the oxygen-istope scale, from 27 to 58 ka (Morley and Hays 1981).

Data from 31 Middle Valdai sediment sections are listed in Table 2, and include only those studied by palynological or paleocarpological methods. The oldest date was determined for the Rokai section near Kaunas: 52 ka t 1.69 ka. Pollen data indicate that tundra-forest vegetation expanded at this time (Gajgalas et al. 1987). Late Pleistocene Chronology of European Russia 423

TABLE 2.14C Dates of Organic Remnants from Middle Valdai Sediments

Lab no. 14C age (BP) Section location, sample material, depth LU-28C 25,440 t 270 Dunaevo, Lovat River basin, peat from 6.4 m LU-28B 25,600 t 360 Dunaevo, Lovat River basin, peat from 6.4 m LU-1237 26,980 t 590 Njom, river basin, peat from 5.2 m LU-105 28,170 t 750 Belorussia; plant detritus LU-646 29,080 t 580 Novomonchalovo, near t. , Tver region, wood LU-107 31,470 t 590 Shenskoje, at Kesma River, Tver region, wood from 4.5 m LU-339 32,650 t 720 Shenskoje, Kesma river exposure, Tver region, borehole, peat from 9.7-10 m LU-1319 31,100 t 730 Mamyl, River, , peat from 13 m LU-159 32,260 t 730 Lejasziemes, Gauja River, Latvia, plant detritus from upper layer LU-311 34,500 t 790 Lejasziemes, Gauja River, Latvia, plant detritus from lower layer LU-1633 33,460 t 1060 Birzhai, Lithuania, borehole LU-1149A 33,100 t 850 Michalinovo, near Vitehsk, Belorussia, plant detritus, coarse fraction LU-1149B 34,040 t 350 Michalinovo, near Vitehsk, Belorussia, plant detritus, fine fraction LU-645 33,690 t 360 Novomonchalovo, near t. Rzev, Tver region, wood LU-513A 33,520 t 470 Sozva River, Lower Pechora basin, peat, insoluble fraction LU-513B 34,540 t 1570 Same sample, soluble (in 2% NaOH) fraction LU-92A 36,400 t 800 Shapurovo, near Surazh, Belorussia, peat LU-1620 36,360 t 1300 Shapurovo, near Surazh, Belorussia, peat LU-98 37,960 t 1000 Sloboda, near Surazh, Belorussia, peat LU-150 37,200 t 910 Vjazynka, 30 km NW from Minsk, peat LU-599 38,230 t 240 Dzhiguta, near Sukhumi, wood from 1.75-1.90 m LU-512A 38,670 t 870 Tyrybei, Hvostovaja River, Lower Pechora basin, peat, insoluble fraction LU-512B 39,840 t 570 Tyrybei, Hvostovaja River, Lower Pechora basin, peat, soluble fraction LU-588 39,170 t 470 Kyltovka, Vychegda River basin, Komi ASSR., wood from 4.7-4.9 m LU-63 39,800 t 800 Grazhdansky prospect borehole, N Leningrad, peat LU-22 40,380 t 800 Grazhdansky prospect borehole, N Leningrad, peat LU-15A 40,490 t 870 , Tver region, coarse fraction LU-15B 41,700 t 730 Same sample, fine fraction LU-550 40,650 t 790 Shapkino II, Shapkina River, lower Pechora basin, peat LU-517B 40,860 t 1260 Shapkino II, Shapkina River, lower Pechora basin, peat LU-94 40,800 t 1900 Suchona near v. Selische, region, peat from 20.0-20.2 m LU-93 41,100 t 1500 Same borehole, peat from 19.75-20.0 m LU-632 41,810 t 600 Kileshino, near Selizharovo, Tver region, wood LU-648 41,200 t 710 Dzhiguta, near Sukhumi, wood from 3.7-3.9 m LU-647A 42,760 t 660 Dzhiguta, near Sukhumi, wood from 4.7-4.8 m LU-606 44,130 t 630 Dzhiguta, near Sukhumi, wood from 5.0-5.1 m LU-181 41,290 t 320 Dolgopolka, near Tutaev, Jaroslavl region, wood LU-533 42,810 t 1200 Urdjuga, Malozemelskaja tundra, peat LU-519 42,660 t 970 Shapkina I, Shapkina River, lower Pechora basin, peat LU-596 43,300 t 780 Vaskelovo, near Leningrad, peat LU-1053 43,440 t 1460 Jula, river basin, Arkhangelsk region, peat LU-1262 45,000 t 1150 Same exposure, wood LU-1206 45,210 t 1430 Juizh, North Dvina basin, Arkhangelsk region, peat LU-673 45,770 t 1160 Chernaja Rechka, near Leningrad, peat from 2.8 m LU-164 46,030 t 1710 Krasnaja Gorka, Dneiper River, Belorussia, peat from 6-7 cm top peat layer LU-186 46,770 t 830 Krasnaja Gorka, Dneiper River, Belorussia, peat from 12-15 cm LU-133 45,260 t 800 Krasnaja Gorka, Dneiper River, Belorussia, peat from 18-21 cm LU-624 46,880 ±. 1270 Bor, exposure on Lower Pechora, peat LU-674 47,410 t 1270 Chernaja River, Bolshezemelskaja tundra, wood LU-566 47,520 t 1000 Kyltovka, Vychegda River basin, wood from 11.1-11.3 m LU-601 47,320 t 1050 Dzhiguta, near Sukhumi, wood from 5.85-5.95 m LU-1438 52,000 t 1690 Rokaj, near Kaunas, Lithuania, wood 424 Kh. A. Arslanov

At 48-45 ka BP, climatic conditions in the northeastern Russian plain (North Dvina, Vychegda and Pechora basins) were similar to the present (Arslanov et al. 1980b, 1984). From 45-42 ka, cooling had set in. A grass community of wormwoods and a yernik-tundra were widespread at the time. Later, between 42.5 ka and 38 ka, warming occurred and forest vegetation appeared (Arslanov et a!. 1980b). Two warming phases can be distinguished during the Middle Valdai. The first, the Krasnogorsky (Rokai) and "Grazhdansky prospect" interstadials, occurred in the interval, 52 ka-36 ka. Cooling occurred at 45 ka-42.5 ka on the northeastern Russian plain. The second Middle Valdai warming, the Dunaevo interstadial (Brjansk interval in periglacial regions) took place from 32 ka-25 ka. The Lejasziemes cooling interval (36 ka-32 ka) divided these two warm phases. At the cooling maximum, 34 ka-33 ka, grass tundra was present in Latvia (Lejasziemes), in northeastern Belorussia (Michalinovo) and in the Lower Pechora basin (Soz'va) (Arslanov et a!. 1980b, 1981; Yoznjachuk et al. 1981). This major northern hemisphere cooling was noted in western Europe (between the Denekamp and Hengello interstadials) in (Konoshelsk climatic deterioration) and in North America (Cherrytry glacial stage). During the Dunaevo interstadial on the Russian plain, birch-pine and fir-pine forests dominated in the northeast (Dunaevo), central (Shenskoje, Novomongolovo) and northwest regions (Spiridonova et al. 1981). The three climatic phases, interstadial "Grazhdansky prospect" (45 ka-36 ka), Lejasziemes cooling (36 ka-32 ka) and Dunaevo interstadial (32 ka-25 ka), are comparable to three climatic phases in Siberia, western Europe and North America during the same period. These phases also correspond to oxygen-isotope stage 3 (Arslanov 1975). Abrupt Middle Valdai warming was observed in middle and high latitudes from west to east (Arslanov 1975). During its optimum (48 ka-45 ka and 42 ka-39 ka), low bush-tundra dominated in regions adjoining the Ocean and ; forest tundra was present near the northern taiga border, in Belorussia, and a northern taiga was present in northwestern and central regions of the Russian plain. Taiga forests similar to recent ones spread north of the Dvina River and Vychegda basin. Discontinuous fir-pine-birch forests of the northern Pechora basin are expanded to the coast, farther north than at present.

From 48 ka to 45 ka, the forest formation (Shapkino I, II, Sozva, Ghernaja River, Urduga, Tarubei sections) was distributed on the area of recent forest tundra, Bolszezemelskaja and Alozemelskaja (Arslanov et al. 1980b). Obviously, Middle Valdai optima were typical interstadial stages in western and central regions of the Russian Plain. The interglacial is termed the Kargino in Siberia. A mirror-like situation was observed in (Lamb 1977). Thus, Europe and eastern North America were under cold climatic conditions in the Middle Worm. This could be a result of 1) the close proximity of the Laurentian and Scandian continental ice sheets; 2) a warm current, the Gulf Stream, circulated no farther than 55°N (Ruddiman and McIntire 1977), causing cooling in western Europe and in the western part of the Russian plain. Regions distant from the Laurentian and Scandian ice sheets and from the cold Atlantic Ocean (northeastern Russian Plain, Siberia, central and western Canada) were under interglacial climatic conditions in the Middle Wurm. This was probably caused by high summer insolation in the high latitudes at 55-40 ka. The degree of insolation was just below that during the Mikulino interglacial and optimum (Arslanov 1975, 1982). Comparison of climatic-geochronologic data for two sections, Chernaja near the Barents Sea and Dziguta near Sukhumi, revealed that the Chernaja area had a coniferous forest with small birch admixture at 47 ka (Middle Valdai optimum) instead of recent forest-tundra. At the same time, silver fir and spruce forest with beech admixture dominated in the Sukhumi region; such vegetation can be observed now at >1200 m asl (Arslanov et al. 1980a). Late Pleistocene Chronology of European Russia 425

LATE VALDAI GLACIAL STAGE AND DEGLACIATION The Valdai glacial maximum has not been definitely dated. Some scientists believe the Early Valdai stage to be the maximum. I believe that the maximum occurred in the Late Valdai, based on 14C dates from organic remains from sediments overlain by moraine deposits of the glacial maximum from western Belorussia to the Pechora basin. Table 3 shows data for eight sections. Other results suggest that submoraine organic layers formed during the Middle Valdai non-glacial interval. There appear to be no Middle Valdai glacial intervals in western Europe nor on the Rus- sian plain, so the Middle Valdai age of submoraine sediments indicates that overlying glacial sediments were deposited during Late Valdai glaciation. This conclusion is supported by oxygen-isotopic data, with the maximum southward drift of the polar front at 17 ka-18 ka and by

TABLE 3.14C Ages of Valdai Submoraine Organic Sediments

Lab no. Age Section location, sample material

LU-616A 16,650 t 150 Rubezhniza, 7 km SE of Liosno, Belorussia, plant detritus LU-616B 19,270 t 770 Same sample, soluble (in 2% NaOH) fraction LU-1148A 16,950 t 120 Chizhovka, Dubrovno region, near Vitebsk, plant detritus LU-1148C 16,540 t 150 Same sample, soluble fraction LU-95A 17,700 t 170 Drichaluki, 2.5 km N of Surazh, Belorussia, plant detritus, upper layer LU-96 18,370 t 180 Drichaluki, plant detritus, middle layer LU-1756 19,780 t 150 Drichaluki, plant detritus, middle layer LU-1810 17,430 t 1780 Drichaluki, arcto-boreal plants LU-1619 24,690 t 370 Drichaluki, plant detritus, lower layer LU-1618 21,110 t 590 Drichaluki, plant detritus, lower layer, arcto-boreal LU-615A 21,080 t 340 Kasplane, 5 km from Surazh, plant detritus LU-615B 19,550 t 190 Same sample, soluble fraction LU-91 22,500 t 210 Shapurovo, 3 km SE of Surazh, plant detritus from 1.8 m LU-18B 21,410 t 150 Puchka, near v. Pokrovskoje, Kubenskoje Lake basin, Vologda region, peat and wood from 6.2 m LU-18A 21,880 t 110 Same sample, cellulose LU-90A 25,100 t 240 Gozha,13 km N of Grodno, Neman River, peat, fraction it mm LU-90B 24,860 f 230 Same sample, fraction s1 mm LU-1616A 26,610 t 220 Irkhino, western bank of Kubenskoje lake, Vologda region, peat LU-1616B 32,090 t 450 Same layer, wood LU-1149A 33,100 t 850 Mikhalinovo, 8 km SW of Liosno, Belorussia, plant detritus, fraction 20.25 mm LU-1149B 34,040 t 350 Same sample, fraction s0.25 mm LU-1257 34,030 t 810 Tomasha, Tomasha river, 3.6 km from the mouth, Arkhangelsk, gyttja LU-399 38,900 t 480 Kileshino, 4 km N of Selizharovo, Tver region, wood from peat lens in moraine LU-525 39,610 t 490 Kileshino, wood from peat lens in moraine LU-527 46,670 t 910 Same exposure, wood from moraine LU-632 41,810 t 600 Same section, wood under sand, with gravel and boulder LU-513A 33,520 t 470 Sozva-1, Sozva river, tributary of the Pechora River, peat under limno- glacial sediments LU-1113 40,680 t 1180 Sozva-2, the section at the same locality, peat under moraine LU-533 42,810 t 1200 Urdjuga, Sula River basin, Pechora tributary, peat under moraine (5 dates) 40,650 t 790 to Shapkina I, II, Shapkina River, Lower Pechora basin; peat under moraine 45.280 f 1200 426 Kh. A. Arslanov

CLIMAP data on the maximum distribution of the Laurentian and Scandian ice sheets at 18 ka-20 ka (Belenger 1982; CLIMAP 1975, 1985).

Short-term warming occurred after the Late Pleistocene glacial maximum (Arslanov 1975). Organic sediments correlated with the interval mentioned above have not been identified on the Russian plain. This phase was followed by abrupt cooling 16.5-15 ka; morainal Veps-stage sediments formed on the Russian plain at this time. Events following the second glacial maximum are established: Raunis, Bulling, Allerod, divided by Oldest, Older, and cooling. Recently, two new Raunis interstadial sections were studied in Latvia: Burzava and Jidumnicki (Arslanov et al. 1981). Interstadial peat dates to 13 ka.

CONCLUSION Table 4 presents the Late Pleistocene time scale for European Russia. Names of interstadials and cooling phases correspond to the names of sections where they were first studied (Dunzaevo, Lejasziemes, Michalinovo, "Grazhdansky prospect", Shapkina, Krasnaja Gorka, Shestichino, Jonenis I, II, Tosno).

TABLE 4. Late Pleistocene Geochronology Scale of European Russia

Climatic-geochronologic subdivision Age (x 103) BP Oxygen isotope stage

Holocene 1 Valdai glaciation Late Valdai stages and interstadials Younger Dryas 11.0-10.0 2 Allerod 11.8-11.0 2 12.0-11.8 2 Bulling 12.4-12.0 2 12.4-13.0 2 Raunis interstadial 13.7-13.0 2 Veps stage 15.0-13.7 2 Climatic amelioration 16.5-15.0 2 Max stage Bologoje - Edrovo stage 25.0-16.5 2 Middle Valdai mega-interstadial Dunaevo (Brjansk) interstadial 32.0-25.0 3 Lejaszieme (Michalinovo) 3 Climatic deterioration 36.0-32.0 3 Interstadial "Grazdanskij prospect" 42.5-36.0 3 Shapkino climatic deterioration 45.0-42.5 3 Krasnogorsk (Rokaj) interstadial 58.0-45.0 3 Early Valdai stages and interstadials Shestikhino climatic deterioration 72.0-58.0 4 Kruglizy interstadial (Jonenis II) 85.0-72.0 5a Climatic deterioration 95.0-85.0 Sb Tosno interstadial (Jonenis I; Upper ) 100-95.0 Sc Late Pleistocene Chronology of European Russia 427

REFERENCES

Arslanov, Kh. A. 1975 Upper Pleistocene radiocarbon variations in surface sea waters by 14C and geochronology of the European part of USSR. dating of marine shells. In Astrophysical Phenomena Bulletin of the Commission for Studies in the and Radiocarbon. Tbilisi, Tbilisi University Press: Period 43: 3-25. 407-422. 1982 Radiocarbon chronology of the Valdaj Belenger, R. E. 1982 Paleooceanography of the Norwe- Epoch on the Russian Plain. Abstract. Moscow, XI gian Sea during the past 130,000 : Cocco- INQUA Congress 2: 12. lithophorid and foraminiferal. Boreas 11(1): 29-36. 1987 Radiocarbon: Geochemistry and Geochro- Berglund, B. E. and Lagerlund, E. 1981 and nology. Leningrad, Leningrad University Press: 300 Weichseliam of south Sweden. Boreas p. 10(4): 323-362. Arslanov, Kh. A., Evzerov, V. Ja., Tertychny, N. I., CLIMAP Project Members 1976. Science 191: 1131- Gerasimova, S. A. and Lokshin, N. V. 1981 On the 1137. age of Boreal transgression sediments on the Kola Gajgalas, A. I., Arslanov, Kb. A., Banis, Ju. Ju., Kazarz- peninsula. In Pleistocene Glaciation on the East- eva, T. I. and Tertychnaja, T. V. 1987 Radiocarbon European Plain. Moscow: 28-37. data of Late Pleistocene, Holocene and archaeological Arslanov, Kh. A., Gej, N. A., Izmajlov, Ja. A., Lok- sites in Lithuania. New Data on the Geochronology shin, N. V., Gerasimova, S. A. and Tertychny, N. I. of the Quaternary Period Moscow, Nauka: 88-97. 1983 On the age and climatic conditions of sediment Lamb, H. H. 1977 Climatic analysis. Philosophical formation on Late Pleistocene sea terraces on the Transactions of the Royal Society of London B280: Kerch strait coast. Vestnik Leningradskogo Universi- 341-350. teta 12: 69-80. Morley, J. J. and Hays, J. D. 1981 Toward a high-reso- Arslanov, Kh. A., Gej, N. A., Ljadov, V. V. and Ter- lution, global deep-sea chronology for the last 75,000 tychnaja, T. V. 1980a New data on Middle Wurm years. Earth and Planetary Science Letters 53(3): geochronology and paleogeography in Abkhazia. In 279-295. Geokhronologija ChetvertichnogoPerioda. Moscow: Ruddiman, W. F. and McIntire, A. 1977 Late 131-138. Quatemary surface ocean kinematics and climatic Arslanov, Kh. A., Kondratene, 0. P., Krukle, M. Ja., change in the high-latitude North Atlantic. Journal of Stelle, V. A. and Ljadov, V. V. 1981 On the Geophysical Research 82(27) 3877-3887. geochronology and paleogeography of the Xaunis Spiridonova, E. A., Arslanov, Kh. A., Malakhovskij, D. interstadial in the Late Pleistocene in Latvia. Vestnik B., Velichkevich, F. Ju., Denisenkov, V. P., Latyshe- Leningradskogo Universiteta 6: 96-102. va, N. M. and Ljadov, V. V. 1981 Pleistocene Arslanov, Kh. A., Lavrov, A. S., Ljadov, V. V., Nikifor- sediment section near Selizharovo (Upper Volga). In ova, L. D., Potapenko, L. M. and Tertychnaja, T. V. Palynology of the Pleistocene and Holocene. 1980b Radiocarbon geochronology and paleogeogra- Leningrad, Leningrad University Press: 32-45. phy of the Middle Valdaj interval and last glacial Velichko, A. A. 1977 A trial of paleogeographic recon- shield on the northeast Russian Plain. Moscow, Geo- struction of Upper Pleistocene conditions for the khronologija Chetvertichnogo Perioda: 68-81. European part of USSR. Izvestija Akademii Nauk Arslanov, Kh. A., Levina, N. B., Ostanin V. E., Bara- SSSR, Serija Geographicheskaja 4: 28-44. nova, V. N., Smirnova, V. M. and Tertychnaja, T. V. Voznjachuk, L. N., Sanko, A. F., Arslanov, Kh. A., 1984 On the geochronology and paleogeography of Ljadov, V. V. and Tertychnaja, T. V. 1981 On the the Late Pleistocene and Early Holocene in the North geochronology and paleogeography of the Middle Dvina basin. VestnikLeningradskogo Universiteta 12: and Late Valdaj in the eastern part of the Belorussian 57-66. lake region. Isotopic and Geochemical Methods in Arslanov, Kh. A., Tertychny, N. I., Gerasimova, S. A. Biology, Geology and Archeology. Tartu, Estonian and Lokshin, N. V. 1976 Sea mollusk shell dating by SSR Academy of Science: 24-27. the 6Th/4U method. Geokhimija 11: 1724-1734. Woillard, G. M. and Mook, W. G. 1982 Carbon-14 Arslanov, Kh. A., Tertychny, N. I., Lokshin, N. V., dates at Grande Pile: Correlation of land and sea Gerasimov, S. A., Tertychnaja, T. V., Filonov, B. A. chronologies. Science 215: 159-161. and Chernov, S. B. 1978 Study of 14C-concentration